X-ray imaging is a technology that uses an X-ray scanner to scan an object to generate an X-ray image of the object. The X-ray imaging technology has been widely used in medical diagnosis, radiation therapy planning, surgery planning and other medical procedures. In existing X-ray imaging technology, there may be some problems in positioning of the X-ray scanner. For example, before a surgery, a doctor may determine an entry point on the surface of a patient. The existing X-ray scanner may include no equipment configured to indicate the entry point. A doctor may usually determine the entry point manually. Therefore, it is desirable to provide systems and methods for X-ray imaging to solve the problems in positioning of the X-ray scanner.